Method of making rolls



Patented `an. 7, 1,930

UNITED STATES PATENT OFFICE GEORGE N. VAN DERHOFROF MISHAWAKA, INDIANA,ASSIGNOR TO DODGE MANUFAC- TURING CORPORATION, OF MISHAWAKA, INDIANA, ACORPORATION OIE" DELA.-

WARE

METHOD 0F MAKING ROLLS i Original application filed June 22, 1927,Serial No. 200,566. Divided and this Serial No. 293,272.

This invention relates to the manufacture of rolls such as conveyorrolls, and aims to provide a practicable method of making a hollow castiron roll which will be substantially axially balanced, obviating thenecessity for expensive and laborious balancing operation required inthemanufacture of present day rolls of this character.

This application is a division of my earlier filed application SerialNo. 200,566, filed June 22, 19277 in which I claim'as `an article ofmanufacture a roll made in accordance with the present invention.

The above and other objects will be more fully apparent and set forth inthe following specification and illustrated in the accompanying drawing,in which Fig. 1 is a longitudinal secton through a roll made accordingto my invention, the supporting means and adjacent roll ends beingillustrated in elevation; y

Fig. 2 is a diagrammatic section of a portion of a mold and coreemployed in my method; and y Fig. 3 is a longitudinal section throughthe end of a roll cast according to my process.

Figs. 2 and 3 illustrate in an exaggerated manner the effect of thefailure to properly center the core in the mold, which failure producesan unbalanced casting.

10 indicates the roll generally, preferably cast of ironJ comprisingr ahollow cylindrical body having the extended rim 11 With the concavedwebs 12 at each end, the webs being imperforate in the form illustratedexcept for central axle openings.

In casting the roll the hollow interior is formed by use of a core 14cylindrical in shape and having at each end a projecting end portion 15connected with the main body of the core by the narrow neck 16 whichforms the bearing recesses 13 in the roll web 12.

In forming the core the projecting ends 15 are made exactly co-axialwith the axis of the main body of the core 14 and are provided with aconvex face which forms the dished or concave surface 17 of the roll web(see Figs. 2 and 3). This surface 17 is therefore coaxial with the corebody 14 and therefore with the cylindrical inner surface 18 of theapplication filed J' uly 16, 1928.

roll. The core is readily and accurately positioned in the mold by meansof the projecting end portions 15 which support the body of the core 14in spacedrelation from the surrounding mold to effect the casting of theWall and the rim 11 of the roller 10.

If the core be improperly positioned in the mold or if it be displacedduring the formation of the mold so that its longitudinal axis does notexactly coincide with the axis of the cylindrical surface 21 of themold, the rim of the casting will be of non-uniform thickness, asillustrated in exaggerated manner by the dot anddash line in Figs. `2and 3. Obviously, this results in an unbalanced roll. Notwithstandingthis defect in a roll, the su:` faces 17 of the casting will always beco-axial with the interior cylindrical wall `surface 18.

In practicing my method, after the casting has been removed from themold and the intcrior thereof cleaned out, the casting is mounted inanishing machine (such as a boring mill or lathe) by engagement ofthemachine with the concave surface or surfaces 17 so that the operatingaxis of the machine Will be co-axial with the concave surfaces 17 andtherefore co-axial with the cylindrical inner wall 18. Utilizing thismeans of centering the roll, they bearing recesses 13 and the outersurface ofthe rim may be finished by any process such as boring, turningor grinding until the outer surface of the roll is fully concentricwith'the operating axis of the machine. f

For example, the bearing recesses 13 at the endsv of the roll may bebored out and reamed to exact size and accurately centered withreference to the axis of the cylindrical inner surface 18. In this casesuch operation includes the finishing and centering of the surfaces 22and 23 of the bearing recesses. By this process offinishing, the exactlongitudinal alignment of the opposite bearing recesses is insured.

While the roll is thus centered or by centering it by the use of theaccurately centered bearing recesses, the outer surface of the roll isfinished by grinding, for example, until such surface is fully orsubstantially concentric with the inner surface 18. This operationobviously cures the non-uniformity of the metal distribution in the rimof the roller, as illustrated in Figs. 2 and 3. The grinding orfinishing may be continued, if desired, to bring the thickness of therim 11 to any desired measurement or to reduce the weight of the roll toa point consistent with the strength requirement.

From the foregoing, it will be seen that a hollow cast iron rollhavingintegral heads and hubs, provided in this instance by the Webs 12 setinwardly from the ends of the roll and formed with inwardly extendinghub portions in which the bearing recesses 1.3 are provided, is cast ona cylindrical core having annular recesses arranged and shaped forcasting the said heads and hubs. The outer walls of these recesses areon the core extensions 15, thus providing mold surfaces for shaping theroll ends exteriorly, which surfaces are coaxial with and in fixedrelation to the main body of the core and are formed to provide the rollends with chucking surfaces, typified by the concaved surfaces 17, whichdefine or locate a center coincident with the core axis or with the axisof the interior cylindrical surface -of the roll cast on such core. Forat least the first machining operation, the roll is mounted by chuekingthe said chucking surfaces, thus locating the working axis for themachining operation coincidentally with the axis of the interiorcylindrical surface of the roll, and insuring the machining trulyconcentrically with said interior cylindrical surface. In practice, theroll being centered with reference to said interior cylindrical surfaceby chucking the said surfaces 17, the

first machining operation is preferably the boring and, finishing of thebearing recesses 13 in the hubs; and for the subsequent machiningoperations the roll may be chucked either by the said surfaces 17 or bythe bearing recesses accurately centered in relation thereto, and theroll may be exteri-orly machined in true concentricity with its interiorsurface, as before explained.

By means of this process it is possible to make a roll of minimum rimthickness without running the risk of developing any regions which areof less than minimum thickness; and the tolerance usually allowed fordefects and inaccurate casting may be considerably reduced. It alsoeliminates the necessity for subsequent balancing adjustment which islaborious and consequently an expensive operation.

By the above described process, all parts of the roll are finished so asto be co-axial with the axis 0f the interior cylindrical surface of theroll and are rendered uniform in dimension so as to effect an axialbalancing of the roll and to insure that the axis of rota- Vtion of theroll will coincide with the axis of the inner and outer cylindricalsurfaces of the roll. This is particularly advantageous in conveyorrolls and the like, where with long conveyor belts the friction of alarge number of unbalanced rolls on the expensive belt would not onlycause a serious wearing of the belt, but would require a much strongerbelt because of the increase in tension on the belt due to theunbalanced rolls. Since a conveyor belt is costly and a very large itemof expense in a conveyor system of this character, smoothly running andwell balanced rolls permita substantial reduction in belt thickness andtherefore in cost of the belt.

A cast roll of this charatcer is well suited to resist the destructivewear which often results in other types of rolls, particularly Where theconveyor handles abrasive material.

ln the form illustrated, the roll is provided with roller bearingsmounted in the bearing recesses adjacent each end of the rolls. .Suchbearings comprise the cup 24 having a tapered surface and`advantageously forced into the recess 13 by a press lit, and the conehaving a tapered bearing surface, the cone being forced by a press fiton the roll shaft 26. Between the rings are series of tapered bearingrollers 27 held uniformly separated by the cage 28. The exact alignmentof the bearing recesses 13 makes it possible to locate the bearing cupaxis co-axial with the bearing cone land shaft axis, thereby insuringproper operation of the bearings. Surrounding the shaft and spacedtherefrom is a. grease tube 29 extending through the roll and having itsends tightly beaded at 30 to the flanges 31 projecting inwardly adjacentthe inner edge of the bearing),` recess 13. The beading operation mayplace the tube in sufficient tension to maintain a tight jointthroughout the life of the roll. Tube 29 serves not only a greasereservoir but seals the interior 32 of the casting from anycommunication with either the grease space or the bearings. This isadvantageous in a hollow casting of this character, because of thepossibility that in practice, all core sand or other abrasive materialmay not be removed from the interior of the casting.

The roll is supported by end pieces 33 titting over the opposite ends ofthe roll sha-ft 26 and mounted in supporting members 3l. In thepresentcase the stems of the end pieces 33 enter fairly closely fitted openrecesses 35 in the supports 34 which hold the end pieces suliieientlytightly but enable a roll to be removed simply by liftingl it until theend pieces clear the recesses and supports. The rolls are supplied withlubricant (which need be replenished only at long intervals) through alubricant tube 3G (having an appropriate fitting 37 at the end) by meansof which lubricant may be forced through a registering opening in theend piece 33 and through an opening 38 into the interior 39 of the shaft(which is made hollow for this purpose). The lubricant pipe 36 extendsdownwardly at an angle from the end piece to a point which will permit alubricant supply means to be attached without interrupting the operationof the conveyor. The interior of the roll shaft communicates throughopenings 40 with the space immediately adjacent the bearing. Surpluslubricant may be accumulated not only on the interior of the shaft butin the grease tube 29 surrounding the shaft. j

A vgrease `pipe may be applied to whichever end piece 38 is mostconvenient. In ordinary practice it is necessary to employ only onegrease supply pipe per roll, the passage in the other end piece beingclosed by'an ordinary plug.

Grease sealing means represented by a labyrinth packing (providingsuccessive restricted and enlarged passages) are mounted on each shaftat the outer ends of the bearing. In the present case the labyrinthpacking comprises a disk 4l (providing adjacent its outer edges twoconstricted passages 42 and an intermediate enlarged space) and an outerplate 43, the flange 44 of which enters a circular groove in the end webof the casting and providing further restricted passages which resistescape of grease. A collar 45 comprising an annular flanged plate, fitsin the bearing recess adjacent the bearing and provides an additionalrestricted passage between its inner edge and the ring 25. The greaseseal above described effectively prevents the escape of grease.

Adjacent the grease hole 38 in the shaft is a circumferential recess 46in the shaft 26 which provides a passage for the travel of grease in theevent the hole 39 does not register fully with the end of the greasepipe 36. A set screw 47 in the end piece engages the shaft 26 after thehole 38 has been brought into register with the grease hole in the endpiece and prevents relative rotation. A fastening and adjusting bolt 48is screwed into each end of the shaft and is provided with a washer 49engaging the outer face of the end piece. This bolt may be employed toadjust Vthe bearing to take up for wear by forcing the inner bearingring 25 along the shaft relative to the outer ring 24. A locking memberin the form of a washer having bendable lugs 50 thereon surrounds thebolt 48 and prevents its rotation relative to the end piece. `Thelocking member has an extension 5l extending into a recess 52 in the endpiece so as to prevent rotation of the locking member relative to theend piece. The bendable lugs 50 on the locking member are angularlyspaced a distance corresponding to the angular separation of the faceson the head of a hexagonal bolt, for example, so that the lugs may bebent to bear against such faces.

Obviously the invention is'not limited to the details of theillustrative embodiment thereof herein disclosed, since such details maybe variously modified. Moreover, it is not'indispensable that allfeatures of the invention be used conjointly, since certain features maybe advantageously used (without others) in other methods andcombinations.

The mechanical construction of the roll herein described, and theconveyor-belt supporting structure comprising the rolls, is thesubject-matter of my copending application `Serial No. 367,357, filedMay 3l, 1929, being adivision of the present application.

Having described one embodiment of my invention, I claim:

1. The method of making axially balanced hollow cast iron rolls which ischaracterized by casting the roll with a cylindrical interior surfaceand with end chucking surfaces coaxial therewith, centering the castroll by the said chucking surfaces on an axis which coincides with theaxis of the interior surface of the roll, and then finishing bearingrecesses at the ends of the roll by a machining operation about saidaxis so that the axis of the bearings will coincide with said axis.

2. The method of making axially balanced hollow cast iron rolls which ischaracterized by casting the roll with a cylindrical interior surfaceand with end chucking surfaces coaxial therewith, centering the castroll by the said chucking surfaces on an axis which coincides with theaxis of the interior surface of the roll, finishingy bearing recesses atthe ends of the roll by operation about such axis so that the axis ofthe bearings will coincide with said axis, and then mounting the roll bysuch finished bearing recesses and finishing the outer surface of theroll about such axis so that the roll rim will be of uniform thickness.

8. The method of making hollow cast rolls of the charactervdescribedwhich is characterized `by ycasting the roll with a surface accessibleexternally of the roll having a definite relation with the axis of theinterior cylindrical surface of the roll, then mounting said roll bysuch externally accessible surface on an axis which coincides with saidaxis of said interior" surface, whereby the exterior cylindrical surfaceof the roll may be finished co-axially with said interior surface.

4. The method of making hollow cast rolls of the character describedwhich is characterized by casting the roll with surfaces accessibleexternally of the roll co-axial with the axis of the interiorcylindrical surface of the roll, then mounting said roll by means ofsuch externally accessible surfaces on an axis which coincides with theaxis of said V interior surface, whereby the exterior cylinrical surfaceof the roll may be finished co-axial with said interior surface.

5. The method of making hollow cast rolls of the character describedwhich is characterized by casting the roll with surfaces accessibleexternally of the roll co-axial with the axis of the interiorcylindrical surface of the roll, then mounting said roll by means ofsuch externally accessible surfaces on an axis which coincides with theaxis of said interior surface, and then finishing bearing recesses atthe ends of said roll co-axial with said axis.

6. The method of making hollow cast rolls of the character describedwhich is characterized by casting the roll with surfaces accessibleexternally of the roll co-axial with the axis of the interiorcylindrical surface of the roll, mounting Said roll by means of suchexternally accessible surfaces on an axis which coincides with the axisof said interior surface, finished bearing recesses at the ends of saidroll co-axial with said axis, and then mounting said roll on the axis ofsaid finished bearing recesses and finishing the exterior cylindricalsurface of the roll to provide the roll with a rim of uniform thickness.

7. The method of making hollow cast iron rolls of the kind describedwhich is characterized by casting said rolls with a cylindrical interiorsurface and concave ends of circular cross-section and co-axial withsaid cylindrical interior surface, and then mounting said rolls byengagement with said concave ends on an axis coincident with the axis ofsaid cylindrical interior surface, whereby the roll may be finished onthe exterior in true concentricity with said interior surface.

8. The method of making hollow cast rolls of the character describedwhich is characterized by providing a cylindrical core to form thehollow interior of the casting and shaping the core to provide a surfaceon the exterior of the casting which has a definite relation to the axisof the interior cylindrical surface of the casting, and then mountingsaid casting by means of said surface in afinishing machine so that theaxis of the finishing inachine will be co-axial with the axis of saidinterior cylindrical surface, and then finishing the outer cylindricalsurface of said roll so that it will be co-axial with said interiorsurface.

9. The method of making an axially balanced hollow cylindrical castingwhich is characterized by providing on the core which forms the hollowinterior, an exterior portion which is co-axial with the axis of thecore so that the casting will be provided on its exterior adjacent anend with a surface of circular.cross-section which is co-axial with theinterior cylindrical surface of the cylinder; then mounting said castingin a finishing machine by means of said exterior surface so that theaxis of operation of the machine will be co-axial with the axis of theinterior surface of the cylinder; and then finishing the outercylindrical surface of the cylinder so that it will be co-axial with theaxis of said interior surface, whereby the wall of Said cylinder will beof uniform thickness and will be axially balanced.

lO. rI`he method of making an axially balanced hollow roll with bearingwebs at the ends which is characterized by casting the roll with a corehaving a portion exterior of said roll which is co-axial with theportion which cores out the interior of the casting and which forms aconcave surface of circular cross-section exterior to the end web, thencentering said casting in a finishing machine by means of said concavesurface so that the axis of operation of the machine will be co-axialwith the axis of the cylindrical interior surface of said casting, thenfinishing bearing recesses in said webs so that they will all beco-axial with the axis of said interior cylindrical surface, and then bymounting the roll on the axis of the finished bearing recesses finishingthe exterior surface of said roll co-axially with the interior surfaceso that the roll rim will be of uniform thickness.

ll. The method of making an axially balanced hollow roll with bearingwebs at the ends which is characterized by casting the roll with a corehaving a portion exterior of said roll which is co-axial with theportion which cores out the interior of the casting and which forms aconcave surface of circular cross-section exterior to the end web, thencentering said casting in a finishing machine by means of said concavesurface so that the axis of operation of the machine will be co-axialwith the axis of the cylindrical interior surface of said casting, andthen finishing the bearing portions of said end webs so that saidbearing portions will be co-axial with the of said interior cylindricalsurface.

12. The improved method of manufacturing a hollow cast iron roll whichis characterized by casting the roll with a cylindrical interior surfaceand with end chucking surfaces locating a center coincident with theaxis of the said cylindrical interior surface, mounting the roll for amachining operation by chucking it by the said chucking surfaces,thereby locating the axis for the machining operation coincidentallywith the axis of said cylindrical interior surface, and conducting triemachining operation about the said axis.

13. The improved method of manufacturing a holiow cast iron roll havingintegral heads and hubs, which is characterized by providing acylindrical core with annular recesses arranged and shaped for castingthe said heads and hubs, forming the said recesses to provide the rollheads with exterior chucking surfaces centered coincidentally with theaxis of the core, casting the roll on said core, mounting the roll for amachining' operation by chucking it by the said chucking surfaces,thereby locating the working axis for the machining operationcoincidentally with the axis of the cylindrical interior surface of theroll, and performing the said machining operation about the said axis. Y

14. The improvement in the art o casting a hollow roll, which consistsin casting the roll on a hollow core while casting heads and hubsintegral with the roll between mold surfaces in fixed relation with thecore and formed to provide the roll heads with chucking surfacescentered coincidentally with the core axis, which surfaces may beavailed of for centering the roll for machining.

15. The improvement in the meth-od of making a hollow cast roll, whichis characterized by coring the roll to provide a cylindrical interiorsurface while shaping the ends of the roll casting by molding surfacesin iXed relation and coaxial with the core and formed to provide theends of the roll with surfaces which may be availed oii' for centeringthe roll for a machining operation.

In testimony whereof, I have signed my name to this specification.

GEORGE N. VAN DERHOEF.

